update firebase/php-jwt to 6.4

Author: valery-smolyakov

composer.json

@@ -24,13 +24,13 @@
     ],
     "require": {
         "php": ">=7.0",
-        "firebase/php-jwt": "~3.0 || ~5.0"
+        "firebase/php-jwt": "~3.0 || ~5.0 || ~6.4"
     },
     "require-dev": {
         "codeless/jugglecode": "1.0",
         "friendsofphp/php-cs-fixer": "^2.13",
         "php-coveralls/php-coveralls": "2.1",
-        "phpunit/phpunit": "^6.4 || ^7.4"
+        "phpunit/phpunit": "^6.4 || ^7.4 || ^7.5"
     },
     "autoload": {
         "psr-0": {